Mechanics of Materials and Fracture for High School Students

Abstract

We developed a nine session after-school curriculum to introduce high school students to fracture mechanics through interactive and hands-on experimental exploration of mechanics of materials and structures. Each session begins with a discussion of the week's core concept in the context of a real world example of its application or importance. The remaining time is devoted to small group hands-on activities that reinforce and further explore the concept. The program revolves around the use of a custom designed portable load frame to perform material testing of 3D printed materials and structures. Students are introduced to the load frame during the second session where they determine material properties using a cantilever beam experiment. In the following sessions students focus on individual concepts in the experiment such as the source of the cantilever beam equation or dimensional analysis to determine the units of their results. The final three sessions involve bringing together all the concepts from the previous sessions to try to design the stiffest beam within a constrained cross-sectional area. Students go through the engineering design process from defining the problem to designing and testing prototypes to choosing a final design, 3D printing it, and testing it. Throughout the tests, they collect load and displacement data to calculate the achieved beam stiffness. Additionally, all beams are tested to failure to observe fracture mechanisms and ultimate strength. The primary goals for this program are to reinforce students' prior knowledge from their science classes, demonstrate potential applications of additive manufacturing, and inspire interest in mechanics of materials.

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